This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The current research proposes to use multiple MRI techniques (structural, diffusion tensor, functional MRI, and perfusion), and neurocognitive assessments, to thoroughly characterize the brain effects, and potential cognitive impairments, associated with excess weight gain in adolescents. We plan to do this using a cross sectional design, studying youths who are either normal-weight or obese. Our subjects will be recruited from the IDEA Study longitudinal cohort study - that follows youth (ages 10-16 at baseline) using three yearly data collection periods. The specific research aims and hypotheses are as follows: Aim 1: Determine how greater body mass is associated with brain changes using the following MRI techniques: 1) Structural Imaging;2) Diffusion tensor imaging;3) Functional MRI, and 4) Perfusion MRI. Aim 2: Characterize the effect of body mass on cognition. Considering the pandemic rate of youth obesity, and the lack of explicit brain imaging data available, this research is considered timely and necessary. Results of this investigation are expected to inform medical professionals about the brain mechanisms of obesity - ultimately, towards prevention and treatment of adolescent obesity.